S320p.57 — Double Maxima of 11-year Solar Cycle

Date & Time

Aug 10th at 6:00 PM until 7:30 PM




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Author(s): Valery N. Krivodubskij1

Institution(s): 1. Kyiv National Taras Shevchenko University

We propose a scenario to explain the observed phenomenon of double sunspot cycle maximum, which is attended by five processes of magnetic reconstruction in the solar convection zone (SCZ): Omega effect, magnetic buoyancy, macroscopic turbulent diamagnetism, gradient-rho effect and meridional circulation. It was found that the reconstruction of magnetic fields in the high-latitude and equatorial domains of the SCZ occurs in different ways. Two tides of inner toroidal fields from the lower base of the SCZ to the solar surface in the equatorial domain play a key role in the developed mechanism of double maxima. Deep toroidal fields are excited due to Omega effect near the bottom of the SCZ at the beginning of the cycle. Then these fields are transported to the surface due to combined acting of magnetic buoyancy, macroscopic turbulent diamagnetism and magnetic gradient-rho flow in the equatorial domain. Over time the magnetic fragments can be seen as bipolar sunspot groups in the middle latitudes in the "royal zone". This first wave of toroidal fields, which is directed up, gives the main maximum of sunspot activity. However, the inner toroidal fields in the high-latitude polar domains at the beginning of the cycle are blocked near bottom of the SCZ by two antibuoyancy effects (turbulent diamagnetic transfer and magnetic gradient-rho pumping, which are directed downward). Deep meridional flow toward the equator transports these fields to low latitudes of the equatorial domain (with favorable conditions for magnetic buoyancy) during about 1 2 years. Then "belated" magnetic fields rise up to surface (second tide of toroidal field). This second delayed portion of toroidal fields, rising to the solar surface at low latitudes, leads to second (repeated) sunspot maximum.